Automatic brake adjuster



Patented Jan. l5, 1946 t, A UNITED "STATES -1` ATENTv OFFICE- AUTOMATIC BRAKE ADJ USTER Leon E. "Thibeault, Flint, Mich., a'ssignor of onehalf to Joseph Thibeault, Flint, Mich. Y

-, YApplication April 20, 1'945, Serial No. 589,395`

(Clf 18S-79.5)

4 Claims.

The invention relates to automatic brake adjusters, and has for an object to elect improvements in that type of adjuster illustrated in my Patent No. 2,291,662, issued August 4, 1942.

' An important aim of this invention is to simplify the construction of the device to the end of lowering costs and 'reducing' diiculty in assembly, and at the same time, to ellectv a marked improvement in the functioning of the device.

A particularly important aim of the invention is to simplify the manner of mounting the device upon the assembly plate of an axle or the like, and evenrmore important, to simplify the adjustment of the device to the brake shoe, so that little time need be lost in electing the necessary emplacementof the device, and also, to simplify the adjustment of the compensating device, so that it will work or operate with great certainty, and yet in such manner that its adjustment by inexperienced workmen may be carried out with great certainty,

Itis also an aim to effect a novel manner of mounting the clutch device, to the end that great simplicity in its manufacture and assembly may be eiected. i

Additional objects, advantages and features of inventioncreside in the construction, arrangement and combination of parts, which will be more particularly set forth in the appended description and accompanying drawing, wherein Figure vl is av schematic conventionalized view of a brake inwhich my invention has been in-` corporated.

Figure 2 is an enlarged sectional view of one shoe and my adjuster applied thereto.

Figure 3 is a plan of the blank for the base or housing.

Figure 4 is a plan of the blank for the presser.

Figure l is an elevational view of a brake assembly on an assembly plate III, the brake device being conventionally illustrated, as it may consist of any usual hydraulic double-acting brake in which expanding brake shoes are forced in opposite directions, the operative connections being of any -usual kind, and not being illustrated herein. y

In the' event that the brake operating linkage between the ends of the shoes I I is of such nature that movement of one shoe will involve like movement of the other in the opposite direction, but one of my devices need be installed in each brake, but if necessary, one device may be installed for each shoe, substantially in the relation shown in my prior: patentY mentioned. For this reason, but onedevice will -be described, and where necessary,

may befduplicated at the opposite brake shoe in case two are required.

'Ihe brake includes two arcuate brake shoes I3, substantially as in my prior patent, although they may conform to conventional usage. Two are usually provided in brakes nowgenerally used upon automobiles, being pivoted at one end, and brake operating linkage I5 being connected to their opposite ends and associated with the brake cylinder I6 or other device for thrusting these linkages in opposite directions so as to spread the shoes apart and against the flange II of thel brake drum which is rotatable around the shoes, as usual. These shoes are faced conventionally as at I4, with a renewable material, of suitable frictional quality, which is the principal wearing element of brakes. The brake shoes have the -usual stiiening ange 2|] of planiform shape, and there is conventionally shown a retracting spring 2l hooked between the two shoes to hold them yieldably retracted, which vis a practice in a great many brakes of this kind. Y

On the assembly plate I, closely adjacent one of the shoes there is a small box case housing 23, which is formed of a simple rectangular blank of strap metal having its two endV portions bent at right angles at a distance from the middle of the blank, in the same direction, and then bent inwardly toward each other, the central part constituting a body 24, the downturned intermediate `parts forming end walls 25whi1e the inturned ends constitute base plates 26, the space between their end edges constituting a slct or channel 2,1, with an important function to be subsequently described. The extent of the end walls 25 between the body 24 and the base plates 26 preferably is such as to allow the case to lie against the assembly plate Ill between the latter and theange 2l]V of theshoe. The body portion 24 is oblong, as shown, and in each of the end' walls 25 centrally located openings are formed, in'which there is slidable an adjuster rod 28. A cl-utch block 29 of hardened steel is set in the slot 2l 'adapted to lie parallel to or inclined between the walls 25, in a plane normal to the plate I0, and being apertured to receive the rod 28 loosely, the opening, however, being smoothly bored so that at its ends angular edges are formed. The opening through the clutch plate is suiciently larger than the diameter of the rod 28 to permit the plate 28 to be inclined so that the angular edges around the bore may bind against the rod and so that the plate 29 cannot slip on the rod. A protractile helical spring 30 is engaged around the rod between the clutch plate 23 and that end wall 25 which is next to the shoe, so as to press the plate inwardly from the shoe. The lower edge of the plate 23 is thus held by the slot 21, and the plate Caused to become inclined, as shown in Figure 2. The upper edge of the plate is preferably spaced from the body portion 24 of the housing 23, so as to afford free movement for the clutch plate under the part ,in .A I..

The housing '23.isv preferably lat{sittin-A position on the plate I as to aiord a good clearance between the brake shoe I3 and the adjacent end wall when the brake shoe is `fully retracted with new lining, in place thereon. This retracted position of the newly lined shoe, is approximatelyV each apertured at 36 to receivev fastening screws 31 therethrough, these apertures being located adjacent opposite longitudinal edges of the blank, as shown in Figure 3, and in order to facilitate assembly and emplacement of the screws, somewhat larger openings 38 are formed in the top plate portion 24 of the case, so that a screwdriver may be inserted to enable ready driving of thescrewsf31. 1 2' .From the foregoing, it .wiufbe readily understood that in order to install one of my automatic adjusters upon' brakes already in use, it is only necessary to drill and tap three small holes for the screws and 31 and secure the parts in the as shown in Figure 2, in which position the rod f 28 is adjusted so as to bear against the inner vface of the shoe I3, an ample opposite end portion of positions shown. In the emplacement of the case ,-23 as before noted, it is desirable to locate it as close as practicable to the brake cylinder I3, and

' at a certain fixed spacing from the fully retracted the rod still being projected through the inner wall 25 of the case 23 to be engaged by an automatic adjuster 3l carried by the brake shoe. This adjuster is also a simple blank of strap metal, preferably of somewhat thicker material than that of the case 23. It includes a planiform arm portion '32 and 'a presserl plate or finger 33 bent at right angles thereto. The extremity of the arm 32 is formed with an open longitudinal slot 34, and this end ol.V the arm is laidflat upontlie upper side of the ange 20 of the brake shoe and secured by means of a large-headed screw 35'set through the slot and engaged in the flange 28 so as to clamp the end `ofthe arm 32 againstthe flange 28. When so secured, the arm 32 extends in parallel relation to the assembly plate Ill of theV brake. The arm is `so adjusted with respect to the rod 28 that the finger plate 3'3'fextends toward and in a plane normal to the rod 28, and when the brake-isreleased the finger plate is spaced from the adjacent end of the rod 28 'a distance approximately equal to the space between vthe liningA I4 o'f 'the brake shoe andthe flange II of the drum. 4The vringerstopsshort ofthe plate I0, and islso located that on application of thebrake the arm 32 and finger will bev moved with the shoe 'I3 so that as the lining hl engages with full braking eiiect against the flange H of the drum the finger '32 will stop 'jus-'t at or short of the end of the rod 28.

Thereafter, v`as the lining Il'of'the brake wears away, each time that the brake is applied it will move further toward the flange of the drum, Yand this will permit the finger 33 to engageth'e inner end of 'the rod 28 and thrust it inf-the same direction 'that the brake shoeis moved in application.

When the rod is so moved, vthe thrust plate 2li-will allow this movement freely, any tendencyA of the plate to bind upon the rod 28 causing the fplate to be moved toward'a position at right angles to the `rod 28, so that thev rod' becomes freed and the 'spring 30 is permitted to -hold the lplatt-:f2livin slightly binding engagement with thevrod, so that when pressure is removed from the `rod tending to thrust it toward the brake', the thrust-plate 29; will again rbind 'the rodand hold it 'against return.l The result of engagement 'of fthe rod by the linger 33 iis to cause-the rod to support the she'e 3-3 fafter a slight releasing action, v'so that 'excessive movement of thefshoe from full braking'p'osition wilil'not occur, and in consequencathereafter, only 4moderate and rinorinal operations of "foot pedals and'otherbrake applying meansis required to Amove the 4shoe to fullfbrakingpositionfthroughout the life'of the lining I4.`

'Toename ythe ready :mounting ofthe case T23 upon the assembly base I'Il, the base plates are sol the'brake shoe. In forming the aperture for the screw 35 by whichA the presseri'lnger-is mounted, the latter should be axially centered with a line through the rod 28 and normal to the plate I0, andclose to the inner-edge of the ange 2U. This opening being drilled rand tapped, the lscrew 35 may be engaged therein,`sufcient space between the head thereof and the flange 20 'to permit in' sertionofthe slotted end o'f the arm 32 under 'the' head of the screw so-thatthe shank of the screw is entered in the slot 34. The arm 32 is then adjusted longitudinallyto bring the finger into proper relation to the end of the' rod 28, by slidi-ng the' armunder' the head of the screw while keeping it alined with the rod, untilA the linger 33 just' barely vengages 'the ladjacent end of the rod 28 while the brake is applied,` then tightening the screw to hold t-hearm as adjusted; VIf the brake is newly lined the arm 32 may be slightly backed oil, so'that the linger will clear the rod by, say, s inch. The placement of the case 23 withrespect to the brake shoe I3 should be such as to permit the Ainner endsof' the rod 28 to project from thev casing a distance greater than the movement of the unlined shoe I3'from full retracted position A that the same-device is adapted to use adjacent either of theshoes ina brake without'change of design, and so that 'duplicates Amay be used on 'adjacent shoes in the same brake if needed; and

itis'a further'advantage that where two of the adjuste'rs arevv required in one brake, `they 'do 'not have'tcbe; located at' the same distances from theiivots of the respective brake shoes, as the dev-irse will function with brake shoes having different extents of movement, and lwill function on th'ef's'amefbrake shceat different distances 'from the pivot-of the shoe.

It is apparent that the case 23 is adapted -tc be produced by simple-cutoii and punch-procedures, using simple'-strapstckgand the same is true of 'the adjuster arman-d finger 32-33 and also theclutch 'plate I29, although if desired, -to `assure highfeflie'iency infclutchingth'e rod 28, the Qpening Ithrcmg'hthe plate v29 `is preferablyV bored smooth-ly instead -of punched.

` It Willbe readily understood from thef'forego- 'f5 ing that the 'device fis adapted to be produc'ed'and retailed at a low cost well Within the reach of the every-day motorist, as an accessory to be applied to vehicles already in use. Conversely, it may be adopted by motor vehicle manufacturers as standard equipment without adding objectionably to the cost, but contributing greatly to lowering maintenance costs for the user.

Having disclosed my invention in its best embodiment known to me at this time, it will, nevertheless, be understood that changes in the arrangement, parts, substitution of materials and equivalents, may be made therein without departing from the spirit of the invention within the scope set forth in the appended claims, wherein I claim:

1. An automatic brake adjuster for brakes of the character described comprising a case member adapted to be mounted fixedly in juxtaposition to -a brake shoe, and having a rod slidable therethrough to engage the shoe, said rod exposed at its opposite end a distance beyond the case, and a presser linger for the rod adapted to be fixed on the shoe and movable with the shoe in line with the rod and inwardly thereof to engage the latter under wear of a lining on the shoe, and a clutch device for the rod on the case yieldable to movement of the rod by the presser but adapted to hold it against return. u

2. The article of claim 1 in which said case comprises a strap metal member having opposite end portions bent at right angles to form end walls, said Walls being apertured to receive the said rod therethrough as a guide, and having its construction and combination ofV extremities bent inwardly and stopping short of each other, said clutch device comprising a plate apertured to receive the rod slidably therethrough and having an edge portion set and loosely fitted between the extremities of the strap metal member, and a helical spring around the rod confined between the clutch plate and one of said end walls, said rod being projected beyond both end walls of the case.

3. The article of claim 1, wherein said presser device comprises a strap metal blank having an arm portion adapted to be secured upon a brake shoe and of a length to extend from the shoe beyond the inner end of said case and rod, said blank having a downturned end portion constituting a finger piece movable with the shoe to engage the inner end of said rod.

4. As an improved article of manufacture, a case for rod clutches of the general character described, comprising a sheet metal member having opposite end portions bent in one direction to form end walls, and having its extreme end portions bent inwardly to extend toward each other and stopping short of each other to form a slot therebetween, said end walls being apertured to receive a rod slidably therethrough, said slot being adapted to receive loosely therein a portion of a clutch plate in binding engagement with the rod, at least one of said extreme end portions being shaped and apertured to receive fastenings, the body of the plate thereover being apertured to receive a tool to manipulate the fastenings.

LEON E, THIBEAULT. 

